ACSys TREC-8 Experiments

Experiments relating to TREC-8 Ad Hoc, Web Track (Large and Small) and Query Track tasks are described and results reported. Due to time constraints, only minimal e ort was put into Ad Hoc and Query Track participation. In the Web Track, Google-style PageRanks were calculated for all 18.5 million pages in the VLC2 collection and for the 0.25 million pages in the WT2g collection. Various combinations of content score and PageRank produced no bene t for TREC style ad hoc retrieval. A major goal in the Web Track was to make engineering improvements to permit indexing of the 100 gigabyte collection and subsequent query processing using a single PC. A secondary goal was to achieve last year's performance (obtained with eight DEC Alphas) with less recourse to e ectiveness-harming optimisations. The main goal was achieved and indexing times are comparable to last year's. However, e ectiveness results were worse relative to last year and query processing times were approximately double.